1) Signed written informed consentTarget population2) Subjects undergoing elective unilateral total hip replacement or a revision of at least one component of a total hip replacement.3) Subject must be willing and able to undergo bilateral ascending contrast venography. Unless Investigator/radiologist can assure that a bilateral venogram can be performed, subjects exceeding 300 lbs. (136 kg) and/or BMI ? 35 kg/m2 are to be excluded because of technical limitations due to body habitus.Age and Sex4) Men and women, of any race, at least 18 (or legal age of consent if greater) years of age5) Women of childbearing potential (WOCBP) must be using an adequate method of contraception to avoid pregnancy throughout the treatment period of the study in such a manner that the risk of pregnancy is minimized.

Criterios de exclusión:

Sex and Reproductive Status1) WOCBP who are unwilling or unable to use an acceptable method to avoid pregnancy for the entire treatment period of the study2) Women who are pregnant or breastfeeding3) Women with a positive pregnancy test on enrollment or prior to investigational product administrationTarget Disease Exceptions4) Known or suspected, acquired or bleeding or coagulation disorder in the subject or a first degree relative5) Known or suspected history of heparin-induced thrombocytopenia6) Known coagulopathy7) Active bleeding or at high risk for bleedingMedical History and Concurrent Diseases8) Brain, spinal, ophthalmologic, or major surgery or trauma within the past 90 days9) Active hepatobiliary disease10) Alcohol and/or substance abuse within the past year11) Any condition, in the opinion of the Investigator, for which surgery or administration of an anticoagulant is contraindicatedPhysical and Laboratory Test Findings12) Two consecutive blood pressure readings within 15-30 minutes with supine SBP > 180 mm Hg or supine DBP > 105 mm Hg13) Hemoglobin < 10 g/dL14) Platelet count < 100,000/mm315) Creatinine clearance < 30 mL/min as estimated by the method of Cockcroft and Gault (see protocol Section 6.3.4)16) Active hepatobiliary disease, based on an ALT or AST > 2xULN or a Total Bilirubin ? 1.5xULN (unless an alternative causative factor [e.g., Gilbert’s syndrome] is identified)Allergies and Adverse Drug Reactions17) Hypersensitivity to unfractionated heparin (UFH), low molecular weight heparin (LMWH), porcine products, or iodinated contrast medium (for venogram)Prohibited Treatments and/or Therapies18) Need for ongoing treatment with a parenteral or oral anticoagulant (e.g., subjects with mechanical valves, warfarin eligible atrial fibrillation)19) Current use of dextrans or fibrinolytics20) Treatment with medications affecting coagulation or platelet function unless theycan be withdrawn as follows:• Unfractionated heparin, LMWH, warfarin (or any other VKA), glycoprotein IIb/IIIa inhibitors (e.g., abciximab, eptifibatide, tirofiban) within 4 days before surgery• Clopidogrel, ticlopidine, dipyridamole, sulfinpyrazone within 7 days before surgery• Non-selective NSAIDs with a T1/2 greater than 17 hours within 7 days before surgery• Fondaparinux within 7 days before surgery• Acetylsalicylic acid > 165 mg within 4 days before surgery21) Planned indwelling intrathecal or epidural catheter that can not be removed at least 5 hours prior to first dose of post-operative study drug.Other Exclusion Criteria22) Prisoners or subjects who are compulsorily detained 23) Subjects who have been previously randomized into an apixaban clinical trial24) Administration of any investigational drug currently or within 30 days prior toenrollment into this study

Criterios de valoración:

Composite of adjudicated asymptomatic and symptomatic DVT, non-fatal PE and all-cause death following 35 days of double-blind treatment in subjects undergoing elective total hip replacement surgery.